Lipid-polymer membranes: understanding ion transport through hybrid materials at the nanoscale

离子是带正电荷或负电荷的小原子或分子。自然界中的许多过程，从脑细胞的信号传输到植物将阳光转化为能量，再到电池的性能，都依赖于离子从一个地方到另一个地方的有效和可控的运输。在这个项目中，pi将开发一种新的材料，这种材料将产生控制和增强离子传输的改进方法。随着对高效离子传输需求的增加，需要具有精确定制结构的材料来提供电荷移动的途径以及机械稳健性。聚合物和磷脂是两类可以自组装成纳米级结构的材料，在适当的比例下，它们的杂化可以产生新的纳米离子传输结构。这个项目将支持混合材料的纳米结构和畴的大小如何与机械和传输特性相关联。这个创新的研究项目可以产生新的知识，从而开发出具有成本效益和良性的纳米结构软材料加工方法，用于许多有用的应用，包括分离，水净化和能量储存。pi将提供一些教育活动。首先，她们将参加一个名为“中学女生材料学习聚合物模块”（Mid-GLAM）的夏令营。作为该项目的一部分，pi将准备一个为期一天的模块，在此期间将展示所有材料。这将包括在pi实验室的演示，让学生有机会根据潜在的化学成分来比较具有不同流动特性的材料。目标将是教，在一个动手和引人入胜的方式，如何设计在日常应用中使用的聚合物的性质。该项目将促进对嵌段共聚物-磷脂杂化膜的自组装及其对离子传输的影响的基本理解。虽然嵌段共聚物和磷脂自组装已经分别受到了广泛的关注，但它们的杂化产物可以表现出纳米结构和远程结构域，而这在两种初始组分中都不存在。这项工作的一个关键目的是了解如何利用稳定的双陀螺形态的形成来为离子运输提供连续的途径。杂化材料将被研究以消除界面效应和分子间相互作用的作用。当被限制在纳米尺度时，pi将通过控制膨胀、畴大小和与支撑基质的相互作用来探测离子的迁移率，从而大大增强或抑制离子的迁移率。离子与聚合物的分子间相互作用也将通过聚合物主链上的电荷密度和种类来调节。第二个主要目标是了解在纳米限制条件下导致扩散发生巨大变化的原因。最后，响应光和温度的可触发基团将被纳入嵌段共聚物中，作为在连续和层状纳米结构之间分解和相互转换的手段，以提供调制传输。这项研究将为复杂软材料的自组装、通过纳米结构域的传输以及混合软合金的可逆结构形成提供基本的见解。这项工作将在材料科学系的生物分子材料和动力学课程中传播给本科生和研究生，在那里将讨论自组装过程和时间尺度。调查结果还将通过包括女童学习材料日营在内的外展项目在校园内和社区传播。通过向高中和初中女生介绍令人兴奋的自组装和生物合成混合材料的世界，将促进她们对STEM领域的兴趣。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Ions are small atomic or molecular species that carry a positive or negative charge. Many processes in nature, from the transmission of signals in brain cells to conversion of sunlight into energy by plants to the performance of batteries relies on efficient and controllable transport of ions from one place to another. In this project the PIs will develop a new class of materials that will yield improved methods to control and enhance ion transport. As the demands for efficient ion transport increase, materials with precisely tailored structures are needed to provide both pathways for charges to move as well as mechanical robustness. Polymers and phospholipids are two classes of materials which can self-assemble into structures with nanometer scale features, and in appropriate ratios their hybrids can generate novel nanostructures for ion transport. This project will underpin how nanostructures of hybrid materials and the size of the domains correlates with mechanical and transport properties. This innovative research project can generate new knowledge, resulting in the development of cost effective and benign approaches for the processing of nanostructured soft materials for many useful applications, including separations, water purification, and energy storage. The PIs will offer several educational activities. First, they will participate in a program called Polymers module for Middle-School Girls Learning About Materials (Mid-GLAM) summer camp. As part of this project, the PIs will prepare a day-long module, during which a full span of materials will be showcased. This will include demos in the PIs labs, giving students the opportunity to compare materials with different flow properties based on the underlying chemistry. The goal will be to teach, in a hands-on and engaging manner, how to engineer the properties of polymers which are used in everyday applications. This project will advance the fundamental understanding of self-assembly in block copolymer-phospholipid hybrid membranes and the corresponding impact on ion transport. While block copolymer and phospholipid self-assembly has received much attention individually, their hybrids can exhibit nanostructures and long-range domains which are not present in either of the two starting components. A key aim of this work is to understand how to harness the formation of stable, double gyroid morphologies to provide continuous pathways for ion transport. The hybrid materials will be investigated to deconvolute the roles of interfacial effects and intermolecular interactions. When confined to the nanoscale, ion mobilities can be greatly enhanced or suppressed which the PIs will probe through control of swelling, domain size, and interactions with the supporting substrate. The intermolecular interactions of ions with polymer will also be modulated through the charge density and species on the polymer backbone. Understanding what gives rise to large changes in diffusion under nanoconfined conditions is the second major aim. Finally, triggerable groups which respond to light and temperature will be incorporated into the block copolymer as a means to disassemble and interconvert between continuous and layered nanostructures to provide modulated transport. This research will provide fundamental insights into the self-assembly of complex soft materials, transport through nanostructured domains, and reversible structure formation of hybrid soft alloys. This work will be disseminated to undergraduate and graduate students in coursework including Biomolecular Materials and Kinetics in the Materials Science Department, where the self-assembly process and timescales will be discussed. The findings will also be disseminated both on campus and to the community through outreach projects including day camps for Girls Learning About Materials. Interest in STEM fields will be promoted to high school and middle-school girls, by introducing them to the exciting world of self-assembly and biological-synthetic hybrid materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.